Hi,
I'm not planning to build a dome observatory but just noticed this on All Classifieds
http://www.allclassifieds.com.au/toy...7f6559c9619c15
A steel geodesic style structure 2.9m diam for $150!! A few technical issues, like how to keep strength after cutting the viewing section but maybe some keen DIY could use this.
I have no link to the seller; just noticed it.
Bruce